1. Field of the Invention
The invention relates to a method and a device for controlling the heating of the glow plugs in a diesel engine. Such a method and such a device are used to bring the glow plugs to a predetermined set point temperature at which the engine can be started.
2. Description of Related Art
The publication MTZ 10/2000 xe2x80x9cDas elektronisch gesteuerte Glxc3xchsystem ISS fxc3xcr Dieselmotorenxe2x80x9d [The electronically controlled glow system ISS for diesel engines] discloses a method for controlling the heating of glow plugs in a diesel engine. The glow command or glow requirement is issued after engine control initialization has been completed and after the temperature of the engine elements has been determined by way of the engine control system and subsequent successful establishment of communication between the engine control system and the glow control device.
Since the engine control system in the above method can issue a glow command to the glow control device only after completion of initialization, activation of the glow plugs, i.e., commencement of heating of the glow plugs, is delayed until the engine control system is initialized and the command is transmitted. Therefore, a considerable amount of time elapses before the first successful ignition operations of the engine occurs.
One proposed alternative is to use opening of the doors of a diesel engine vehicle as a start signal for heating the glow plugs. However, this method is often disadvantageous because opening the doors often has no connection with starting of a desired engine. Consequently, the number of heating processes of the glow plugs is unnecessarily increased and the service life of the glow plugs is shortened.
In view of the foregoing, it is an object of the present invention to provide a method and device for controlling the heating of the glow plugs in a diesel engine, wherein the time required for heating the glow plugs can be reduced.
In the present invention, any necessary heating of the glow plugs starts immediately after receipt of a signal for starting the engine, e.g., after switching on the ignition, and after the engine temperature has been determined and evaluated to form a glow command. Therefore, since there is no need to wait for completion of initialization of the engine control system and determination of the temperature is carried out by the glow control system independently of the engine control system, the time required for heating the glow plugs can typically be reduced, for example, by 500 ms.
A preferred embodiment of the present invention is described below with reference to the associated drawings.